What makes us who we are, and what is at the root of personal identity? Those profound questions are at the heart of this expertly crafted novel, a book that is dripping in literary resonance, yet one that also rattles along in wonderful fashion; a very modern thriller with more than a hint of horror about it.
There are echoes of Mary Shelley's Frankenstein throughout Strange Bodies and Theroux has used recent advances in biotech-nology to make his modern equivalent feel eerily plausible.
The book starts when shop owner Susanna is visited by a former university boyfriend, Nicholas. He looks different, but who doesn't after 20 years? However, when Susanna searches online, she finds that Nicholas died the previous year in a road accident, leaving behind a wife and two children.
The rest of the novel is a document that Susanna finds in Nicholas's possession, a confession of sorts that explains everything with such exquisitely creeping dread that it's almost painful to read on as Nicholas gradually gets sucked into the murky world of his worst nightmares.
Nicholas is a minor academic specialising in the work of Samuel Johnson, and is approached by Hunter, a music impresario, and a monosyllabic Russian businessman called Sinan to authenticate some letters which may have been written by the great man.
At first, Nicholas thinks the letters are genuine, but then he becomes suspicious. The prose undoubtedly has the feel and rhythm of Johnson's hand, yet the paper the letters are written on is not nearly old enough.
Eventually he finds out that the letters have been penned by a Russian savant called Jack, the brother of Hunter's housekeeper, who is being kept in Hunter's basement. Nicholas finds himself obsessed with Jack's hulking presence, the contradiction between his lack of everyday communication and his incredible ability to mimic Johnson's work.
It is this obsession that sees Nicholas's life slowly unravel as he becomes drawn into a dangerous world that takes in literary fraud, secret Soviet-era science experiments, and the nature of existence.
Theroux handles the different layers of his story wonderfully as he explores the links between language and identity: without the ability to communicate, what are we? If someone could adequately replicate the communication of another, would the two be distinguishable entities?
In looking at these questions, Theroux draws on literary classics, philosophy and sociology, but he avoids overdoing the intellectual, and always draws the reader back to the emotional core of the novel: Nicholas's struggle to understand who he has become.
There is a deeply melancholic undertow to Strange Bodies, reminiscent of Kazuo Ishiguro's Never Let Me Go; indeed, both books share a morally complex look at mortality. The way in which Theroux portrays his central character's plight and mindset is heartbreaking without ever seeming manipulative.
It's not often you read a book as clever as this that is also emotionally charged and moving. It is to Theroux's immense credit that he pulls it off so convincingly.